Seattle’s sprawling Museum of Flight will double its gallery space with the official opening of a 3-acre Aviation Pavilion this Saturday.

The 9-story roofed outdoor gallery currently displays 15 commercial and military airplanes, including a Boeing 787 Dreamliner, the first Boeng 747 prototype, the only Concorde on the west coast and a FedEx Air Cargo exhibit housed inside a 727 freighter.

Tucked under the wings of the 747 is a mini-airport for kids.

Also on display: a Douglas DC-2 airliner from the 1930s, three big bombers (World War Two’s B-17F Flying Fortress and B-29 Superfortress), and the Cold War’s B-47 Stratojet.

The Museum’s rare, flyable 1932 Boeing 247, Boeing 727 prototype, and the first jet Air Force One will be moved over from the Museum’s Airpark across the street to the Pavilion in the fall.